I worked on this on Thursday and I wasn't able to figure out what was up. I
played with the timing, checked the fuel filter, float bowls, banjo bolts.
Everything looked ok, but it wouldn't even start. I also verified that when
cylinder one is at TDC the large notch is lined up with the pointer.
On Saturday I started getting somewhere. After playing with it a bit more
and cranking a long time, it finally started. I evened up the carbs a little
and both seem to be pretty much in sync now using a hose to listen to the
air flow. I leaned them both out a little too. When the button is pushed up
now it briefly smooths out and then goes rough, but doesn't die. I've got it
timed at 15 deg BTDC with a 7.5 deg distributor. When I rev it up to around
3500-4000 rpm I sometimes get a backfire. What causes that? Also, my major
problem is that spark plug #2 is not firing. I checked this by putting my
timing light sensor on all the spark plug cables and it doesn't light up on
this one. This is what's been causing my huge loss of power.
I did some testing with this trying to determine my point of failure.
Swapped cables with #1, no change, swapped plugs with #1, no change, #2
still not firing. The threads on the hole for #2 are a bit cross threaded,
so it wasn't seated properly either, but after putting it in the right way
and making sure it's seated, it still isn't firing.
Sunday - changed the distributor cap, no change, changed the ignition coil,
no change. I haven't changed the distributor yet and a thought I just had
was to make sure that the distributor is gapping at the right time for #2,
but since it's been working ok up 'til now, I don't think that's the
problem. I don't understand how this problem can be happening since I've
change what I thought could be the faulty parts out of #2, but it doesn't
seem to matter.
Spark goes from the coil, to distributor, through the cap, the wire, and
then the plug. Does it ground against the engine block or back through
itself? I'm guessing the engine block. I feel like I'm beating my head
against a piston here - anyone have any ideas?
Thanks,
Mitch
'69 1600
http://beladi.stormloader.com
-----Original Message-----
From: Mitch Planck [mailto:mitch@ias.net]
Sent: Wednesday, August 16, 2000 4:23 PM
To: 'datsun-roadsters@autox.team.net'
Subject: RE: Roll bars, Timing and Carbs (was: bolt holes)
The consensus is that I'm crazy and that the holes are for the stock roll
bar. Crazy I can accept, the holes thing, I don't know. ;)
Anyways, I checked the timing when I got home - it had slipped a bit. I
hadn't tightened the hold-down bolt enough. The car then proceeded to run
out of gas while sitting in the garage. I put enough in from a gas can to
get to the gas station and also checked the carbs with the little push-up
pins. When pushed up on either carb the engine smooths out at a higher rpm.
Just in the short drive to the gas station I noticed a large increase in
power at lower rpms. Filled up, and went out for a test drive. Much, much
better. No pinging, more power, very nice. This is how I remember it running
15 years ago. I hopped on the highway and drove a couple of miles at about
80mph (since this is Michigan I was being passed anyways). After I got off
the highway engine performance was vastly different and much worse than
before. It made a puttering type noise while trying to accelerate instead of
the normal engine roar. I drove back home with a big pickup right on my tail
and checked the timing again - it hadn't changed. Thinking I had set it
backwards (using the opposite mark for TDC), I reset it. Ran like #$&^%. I
set it back again and it still ran poorly with the occasional backfire. At
this point I gave up.
I think that either I've got the timing all ass-backwards, or the gas
stirred up some sediment.
All the above was written yesterday - crazy day at the office so I couldn't
send it. I did research on timing and distributors on the list archives
today and I'm going to check to see where the pointer marks the timing at
with piston #1 at the top. I'm thinking it's not gas now because I'm getting
backfires.
BTW, I'm going to look at a couple of Roadsters after work tonight, one is a
68 2000, no engine, trans, or carbs, the other is a 70 1600, body off but
sitting on car.
-Mitch
'69 1600
http://beladi.stormloader.com
-----Original Message-----
From: John F Sandhoff [mailto:sandhoff@csus.edu]
Sent: Monday, August 14, 2000 4:57 PM
To: Mitch Planck
Cc: datsun-roadsters@autox.team.net
Subject: Roll bars, Timing and Carbs (was: bolt holes)
Mitch writes:
> I was doing some cleaning on my car this weekend and noticed some odd
holes
> on the rear package deck and behind both seats. I'm thinking that these
are
> bolt holes for a street bar.
Yes, factory mounting points for the factory roll bar.
A couple other comments after reading your web site commentary:
Some people recommend against Armor All, preferring products like
STP that tend to not destroy the underlying foam padding over time.
YMMV and if any Armor All lawyers are reading this, I am just repeating
what I've read elsewhere!
MOST IMPORTANTLY, you mention 'valve clatter' under heavy load. That
noise is the sound of your ENGINE BEING DESTROYED by pre-ignition
i.e. pinging. Your timing is too far advanced. Back it off 'til the noise
goes
away, alternatively start saving up to replace the piston you'll ultimately
burn a hole in :-)
As an aside, since you're twiddling the carbs rather than tuning them (a
minor distinction), keep in mind that if they aren't somewhat in balance,
you can easily be running a pair of cylinders too lean without knowing it.
See above paragraph in regards to saving for new pistons :-) My unisyn
and I don't get along too well, so I use the 'heater hose' technique. Also,
there's a lift pin on each carb that'll raise the piston (underneath side
near the air cleaner. With small hands and some contortion, you can get
to them with the airbox attached). Press one up to raise that carb's
piston and disable it. If the car stalls, the OTHER carb is set too lean.
Oh, add a :-) or two if I sound too serious...
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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